Objective:To compare the difference between active breathing coordinator (ABC) technique and free breathing (FB) mode combined with bodyfix stereotactic radiotherapy (SBRT) for chest tumors.Methods:40 thoracic tumor patients receiving SBRT were randomly selected and divided into the ABC technique group and FB model group. After fixation with bodyfix fixing devices in two groups, cone-beam CT (CBCT) scan images before each SBRT were matched with the plan reference images. The setup errors in the left-right (LR), superior-inferior (SI) and anterior-post (AP) directions were obtained. Then, the setup errors were corrected. SBRT was performed and split intra-fraction CBCT was conducted simultaneously, which was repeated until the end of treatment.Results:In the ABC technique group, the setup errors in the LR, SI and AP directions were (0.25±0.21) cm, (0.28±0.21) cm, and (0.21±0.24) cm, significantly less compared with (0.31±0.22) cm, (0.32±0.21) cm and (0.37±0.23) cm in the FB model group (all P<0.05). The V 30Gy of the heart, the V 20Gy and V 30Gy of the lung in the ABC technique group were significantly less than those in the FB model group (0.31%∶7.35%; 24.5%∶32.9%; 19.5%∶25.8%, all P<0.05). Conclusions:ABC technique combined with bodyfix fixation device may be superior to FB mode in SBRT for chest tumors, which remains to be validated by subsequent studies with large samples.

Objective:To provide a basis for selecting the optimization method for intracavitary/interstitial brachytherapy (IC/ISBT) of cervical cancer by comparing graphical optimization (GO), inverse planning simulated annealing (IPSA), and hybrid inverse planning optimization (HIPO) using dosimetric and radiobiological models.Methods:This study selected 65 patients with cervical cancer who were treated with image-guided IC/ISBT. The afterloading therapy plans for these patients were optimized using GO, IPSA, and HIPO individually, with a prescription dose high-risk clinical target volume (HRCTV) D90 of 6 Gy. The non-parametric Friedman test and the non-parametric Wilcoxon rank test were employed to analyze the differences in duration, dose-volume parameters, and radiobiology between the three types of optimized plans. Results:Inverse planning optimization (IPSA: 46.53 s; HIPO: 98.36 s) took less time than GO (135.03 s). In terms of gross target volume (GTV) dose, the high-dose irradiation V150% (53.66%) was slightly higher in the HIPO-optimized plans, while the V200% (30.29%) was higher in the GO-optimized plans. The GO-optimized plans had a higher conformity index (CI; 0.91) than other plans, showing statistically significant differences. Compared with other plans, the HIPO-optimized plans showed the lowest doses of D1 cm 3 and D2 cm 3 at bladders and rectums and non-statistically significant doses at small intestines ( P > 0.05). In terms of the equivalent uniform biologically effective dose (EUBED) for HRCTV, the HIPO-optimized plans showed a higher value (12.35 Gy) than the GO-optimized plans (12.23 Gy) and the IPSA-optimized plans (12.13 Gy). Moreover, the EUBED at bladders was the lowest (2.38 Gy) in the GO-optimized plans, the EUBED at rectums was the lowest (3.74 Gy) in the HIPO-optimized plans, and the EUBED at small intestines was non-significantly different among the three types of optimized plans ( P = 0.055). There was no significant difference in the tumor control probability (TCP) predicted using the three types of optimized plans ( P > 0.05). The normal tissue complication probabilities (NTCPs) of bladders and rectums predicted using the HIPO-optimized plans were lower than those predicted using the GO- and IPSA-optimized plans( χ2 = 12.95-38.43, P < 0.01), and the NTCP of small intestines did not show significant differences ( P > 0.05). Conclusions:Among the three types of optimization algorithms, inverse optimization takes less time than GO. GO-optimized plans are more conformal than IPSA- and HIPO-optimized plans. HIPO-optimized plans can increase the biological coverage dose of the target volume and reduce the maximum physical/biological exposure and NTCP at bladders and rectums. Therefore, HIPO is recommended preferentially as an optimization algorithm for IC/ISBT for cervical cancer.

Objective The purpose of this study is to investigate the method to reduce the radiation dose to the neck skin in the Tomotherapy treatment plans for early-stage nasopharyngeal carcinoma.Methods The 17 patients with early-stage nasopharyngeal carcinoma that have been treated by the Tomotherapy were selected randomly for this skin sparing study.The neck skin sparing region was generated as an internal margin of 3 mm from the out body contour,excluding the intercrossed area with the targets.Candidate patients were planned using TP and NP method respectively:the TP group was planned with the traditional method.The new neck skin region was considered as an organ at risk (OAR) for planning dose constrain in NP group.The dosimetric metrics of targets and OARs,monitor units (MU) and delivery time were compared as the end points of these two groups.Results The two treatment plan groups satisfied the clinical requirement.There were no significant differences for D98,D95 and D2 of the targets (P ＞ 0.05).The Dmax of brainstem,D1cc of spinal cord,D of right parotid were higher in NP group than in theTPgroup (t =2.47,2.34,2.77,P＜0.05).The Dmax of left mandible joint was lower than TP group(t =2.30,P ＜ 0.05).The V30,V40,V50 and V60 of the skin were considerably lower than TP group (t =8.37,6.02,5.82,4.89,P ＜ 0.05).The mean MU and mean delivery time per fraction of NP group were 6.3％ and 8.1％ less than that of TP group respectively.Conclusions The neck skin region should be delineated as an OAR to be spared in the Tomotherapy treatment planning for early-stage nasopharyngeal carcinoma.This method can reduce the skin radiation dose effectively,alleviate the skin reaction,and improve the life quality of patients in radiotherapy.

Objective To compare dosimetric parameters between automated and manualvolumetric modulated arc therapy(VMAT) plans in the treatment of postoperative cervical cancer patients,and to investigatethe feasibility and dosimetric advantage of the automated VMAT planning.Methods Automated and manual VMAT plans were generated with Pinnacle3 treatment planning system (TPS) for twenty-three postoperative cervical cancer patients,including eight patients in stage Ⅱ A and fifteen in stage Ⅱ B,respectively.The differences in D D95,conformity index (CI) and homogeneity index (HI) of target,as well as dose volume histogram (DVH) of organs at risk (OAR),planning time,average optimization time and monitor unit (MU) were compared between automated and manual VMAT plans.Results The average D CI and HI of automated VMAT plans were better than those of manual VMAT plans (t=4.65-14.92,P ＜0.05).There was no significant difference in D95 (P ＞0.05).The automated VMAT plans achieved better average dosimetric parameters on OARs compared with the manual VMAT plans (t =3.30-14.42,P ＜ 0.05).Automated VMAT plans had a significantly shorter planning time (72 min,t =3.85,P ＜ 0.05) and interruption frequency (twice,t =5.41,P ＜ 0.05) than manual VMAT plans.However,automated VMAT plans had a higher average MU than manual VMAT plans with an average MU of 819 ± 53 and 638 ± 41 for automated and manual VMAT plans,respectively.Conclusions It is feasible to generate automated VMAT plans with Pinnacle3 TPS for postoperative cervical cancer patients.The automated VMAT plans increase the plan quality and reduce the optimization time compare with manual VMAT plans.Automated technique also eliminates the influence of human factors on the plan quality.

Objective To measure and analyze the neutron dose equivalent rate produced by an IORT accelerator with 9 and 12 MeV electron energyies,and compare them with those from a Siemens Primus linear accelerator with the same electron energy,in order to provide data reference for the risk of secondary cancer induced by radiotherapy.Methods Using the neutron detector LB6411,the neutron dose equivalent rates produced by the IORT accelerator of 9 and 12 MeV were measured on some key locations,such as the head of the accelerator,cylinder bottom,patient plane with electron energies 9 and 12 MeV.The similar measurements were also performed on the same locations on a Siemens conventional accelerator.The data were collected and analyzed and the result wer compared between the two accelerators.Results Neutron dose equivalent rates from the IORT accelerator with 9 MeV energy were (51.8±3.1),(45.5 ±1.5),(70.5 ±4.9) and (68.2±3.3) μ Sv/h near the head of the accelerator,cylinder bottom,patient plane,with 5.9％,5.4％,17.8％ and 21.5％ lower than at 12 MeV,respectively.The dose equivalent rates at the similar locations from the Siemens Primus accelerator were (277.3 ±1.2),(285.1 ±1.6),(185.1 ±1.8) and (182.8 ±2.4) μSv/h at 9 MeV,with 48.8％,47.6％,48.7％,52.2％ lower than those at 12 MeV,respectively.At the energy of 12MeV,the neutron equivalent dose rate from the IORT was lower by a factor of about 10 than for Siemens Primus accelerator.Conclusions The neutron dose equivalent rates generaged by both the IORT and the Siemens Primus are higher at 12 MeV than at 9 MeV,which would lead to an increased risk of secondary cancer to patients.The traditional medical accelerator produces much higher neutron dose equivalent rates than the intraoperative electron accelerator,for which the appropriate shielding should be takn.

Objective To investigate the potential dosimetric advantages of half jaw volumetric modulated arc therapy ( H-VMAT) applied to the Oropharyngeal Cancer, comparing with full jaw VMAT (F-VMAT) and intensity modulated radiotherapy ( IMRT ). Methods Planning CT images of 10 oropharyngeal cancer patients were retrospectively chosen and transferred to Eclipse treatment planning system v. 11. 0 (Varian Medical Systems, Pala Alto, USA), based on which H-VMAT, W-VMAT, and IMRT plans were created. Two full arcs (360°) were adopted for VMAT planning, and the 7 beams were equally distributed for IMRT planning. The optimization constraints remained the same for the three kinds of plans. The dosimetric parameters such as D2 , D98 , D50 , HI, and CI were evaluated for PGTV, PCTV1, PCTV2, PGTVln, and PCTVln. In addition, the maximum dose (Dmax) and D1 cc(minimum dose received by 1cc) of the brainstem and spinal cord were analyzed respectively. The mean dose ( Dmean ) to the parotids, oral cave, larynx, and cervical normal tissues were also reviewed. The monitor units ( MU) for all treatment plans were recorded. Results Comparisons of the three planning techniques showed that H-VAMT improved the HI and CI of the targets (except PCTV2) significantly (HI: F =3. 959, 6. 764, 10. 581, 6. 770, 13. 040, P<0. 05;CI:F=6. 594, 4. 138, 0. 842, 4. 031, 5. 388, P<0. 05);reduced Dmax(F=4. 509, 20. 331, P<0. 05) and D1 cc for brainstem and spinal cord (F=27. 432, 26. 314, P<0. 05) significantly;reduced Dmean(F=4. 279, 29. 498, 19. 295, P<0. 05) to the normal tissues of the mouth, throat and neck significantly. The V50 of the mouth and throat were slightly lower in IMRT plans (F=8. 140, P<0. 05). IMRT was slightly better than W-VMAT in sparing oral cavity and larynx, but the dose distribution was the worst. The H-VMAT plans showed the best dose distribution in the cervical normal tissues, especially for the lower and posterior parts, where IMRT plans displayed high dose curves. Conclusions H-VMAT is dosimetrically superior than W-VMAT and IMRT for oropharyngeal cancer, which could be considered for clinical applications.

Cancer-associated fibroblasts (CAF) represent a crucial and abundant group of stromal cells in the tumor microenvironment (TME) and are effective targets for anti-tumor therapy. CAFs exhibit high heterogeneity and plasticity, which play a pivotal role in tumor initiation, progression, immune evasion, and therapy resistance. Radiotherapy (RT) is a fundamental treatment modality for malignant tumors that can reshape the TME through various mechanisms. Following RT, CAFs undergo a series of phenotypic changes and interact with multiple cells in the TME, promoting radioresistance and immune evasion through multiple pathways, such as enhancing tumor cell proliferation, modulating immune response, inducing angiogenesis, remodeling extracellular matrix, and reprogramming metabolism, etc., thereby affecting therapeutic effect. Targeting CAFs in combination with RT can improve anti-tumor efficacy and prognosis. In this article, research progress in CAFs in tumor RT was reviewed.

Brain metastasis is the most common intracranial tumor in adults. Radiotherapy is one of the most important treatments, in addition to drugs, surgery, and other treatments. In recent years, rapid development of targeted therapy and radiosurgical technology has transformed the treatment mode of brain metastases, with increasing emphasis on individualized treatment. However, the mode of radiotherapy in patients with driver gene-positive remains controversial. In this article, the advances in the timing of radiotherapy for brain metastases were reviewed.

Objective:To investigate the diagnosis and treatment of cancer patients in the prefectural and municipal hospitals in Sichuan province during the outbreak of 2019 novel coronavirus disease (COVID-19) epidemic, and analyze the impact of the epidemic on the hospitalization and treatment of cancer patients, aiming to provide reference for the diagnosis and treatment of cancer patients by medical institutions in different provinces.Methods:The prefectural and municipal hospitals in Sichuan province were investigated in the form of questionnaire.Results:A survey was conducted in 37 prefecture-level large and medium-sized hospitals in Sichuan province, of which Grade 3A hospitals accounted for 78.4%. Among the investigated hospitals, the hospitals whose hospitalization index of oncology patients and radiotherapy index of radiotherapy patients were< 1 after the first-class response were 83.7% and 93.1%, respectively. Hospitals with normal or delayed chemotherapy within one-week consisted of 54.1%, and 89.7% of the hospitals received normal radiotherapy or delayed radiotherapy within one-week after the Spring Festival. After the second-class response, the proportion of hospitals with oncology patients and radiotherapy patients that increased after the first-class response was 78.4% and 79.3%, respectively.Conclusions:Under the guidance of the State Council, the Sichuan Provincial Party Committee and the Provincial Government, Health Commission of Sichuan Province, and the municipal health commissions at various levels and under the joint efforts of medical institutions and front-line medical staff from Department of Oncology, a majority of cancer patients admitted to prefectural and municipal hospitals in Sichuan province can receive active and effective treatment during the outbreak of COVID-19 epidemic.

Objective To study the patient movements features during radiotherapy . Methods Randomly selected 120 patients treated in our hospital from February to July on 2016,including 60 thorax treatment and 60 abdomen treatment. The movement data of patient treatment location during radiotherapy treatment was real time monitored by using Sentinel system,movement features of patient′s location during radiotherapy was analyzed. Paired t-test difference. Results During radiotherapy,patient′s treatment location movement types and proportion were motionless type 14. 0%,Moving stable type 64. 0%,Jumping type 8. 7%,increasing type 13. 3%.Patients with thoracic and abdominal radiotherapy,the maximum deviation of IMRT and VMAT treatment were (6.55±2. 34) mm and (4.97±1. 24) mm (P = 0. 002),(3.97±1. 80) mm and (2.69± 1. 42) mm (P = 0. 004).In single treatment,the deviation value of the patient′s treatment location increased gradually with the treatment time increasing and the deviant of thoracic is greater than abdominal at the same time after the treatment beginning. Conclusions Patient′s treatment location movement during radiotherapy is commonly exist,using the technology of VMAT treatment can effectively reduce the treatment site movement of the patient during the treatment and ensure the accuracy of dose.